C语言词法分析扫描器

#include<stdio.h>
#include<string.h>

//定义关键字表
char keyword[10][10]={"int","char","float","if","else","while","break","continue","main","return"};
int len_key=10;

//定义界符表
char del[]={'+','-','*','/','=','(',')','[',']','{','}',';','>','<'};
int len_del=sizeof(del)/sizeof(del[0]);

//定义常数表
#define len_con 10
float con[len_con];
int pos_con=0;

//定义标识符表
#define len_id 20
char id[len_id][10];
int pos_id=0;

//定义保存token的链表
typedef struct _token{
char name[6];//表示识别单词的分类
int pos;//表示识别单词的位置
struct _token *next;
} _token;
_token *token=NULL;
_token *head=NULL;
int IsKeyword(char word[]);
int deal_id(int p,char data[]);
int deal_Num(int p,char data[]);
int IsDel(char check);
int deal_Del(int p,char data[]);

int main()
{
//定义指向token的头指针
    token =(_token *)malloc(sizeof(_token));
    head=token;
//char Data[]="int a = 12.3+e2 ; float b = 20 ; if(a) { a = b;}";
//int Len_Data=sizeof(Data)/sizeof(Data[0])-1;
    FILE *_fp;
int count=0;
    _fp=fopen("in.txt","rb");
char buff[1];
char Data[1000]={'a'};
while(fread(buff,1,1,_fp)!=0)
    {
        Data[count]=buff[0];
        count++;
    }
    fclose(_fp);
int Len_Data=strlen(Data);
int i=0;
for(i;i<Len_Data;i++)
printf("%c",Data[i]);
printf("\n字符串读取完毕\n");
int pos_check=0;
int _start=0;

while(pos_check<Len_Data){

        _start=pos_check;
//处理标识符
if(Data[_start]=='_'||(Data[_start]<='z'&&Data[_start]>='a')||(Data[_start]<='Z'&&Data[_start]>='A')){
printf("进入标识符自动机\n");
            pos_check=deal_id(pos_check,Data);

        }
//处理数字常量
else if(Data[_start]<='9'&&Data[_start]>='0'){
printf("进入数字常量自动机\n");
            pos_check=deal_Num(pos_check,Data);
        }
//处理界符
else if(IsDel(Data[_start])!=-1){
printf("进入界符自动机\n");
            pos_check=deal_Del(pos_check,Data);
        }
else {
printf("error\n");
            pos_check++;
        }
    }
    _token *fp=head;
while(fp->next!=NULL){
printf("<%s,%d>",fp->name,fp->pos);
        fp=fp->next;
    }
return 0;
}

//判断识别出的标识符是否为关键字
int IsKeyword(char word[])
{
int i=0,ans=-1;
for(i;i<len_key;i++)
if(strcmp(word,keyword[i])==0)
    {
        ans=i;
break;
    }
return ans;
}

//对标识符进行处理
int  deal_id(int p,char data[]){
int start = p;
int end = start;
char word[10],c[2];
    p++;
while((data[p]>='a'&&data[p]<='z')||(data[p]>='0'&&data[p]<='9')){
        p++;
    }
    end=p-1;
for(start;start<=end;start++){
         c[0]=data[start];
strcat(word,c);}//这一部分生成拼接出来的单词
printf("\n");
printf("%s\n",word);
strcpy(id[pos_id],word);
strcpy(token->name,"id");
    token->pos=pos_id;
    pos_id++;
if(IsKeyword(word)!=-1)
    {
printf("%s 是关键字\n",word);
strcpy(token->name,"keyword");
        token->pos=IsKeyword(word);
        pos_id--;
    }
printf("<%s,%d>\n",token->name,token->pos);
    token->next=malloc(sizeof(_token));
    token=token->next;
    token->next=NULL;
return p;
}

//计算10的n次幂
float f(int n)
{
float sum=1;
int i=0;
if(n>=0)
for(i;i<n;i++)
            sum*=10;
else
for(i;i<n;i++)
            sum*=0.1;
return sum;
}

//对数字常量进行处理
int deal_Num(int p,char data[]){
int a=0,b=0,c=0,e=0;
float sum=0;
    a=data[p]-0x30;
    p++;
while(1){
while(data[p]<='9'&&data[p]>='0'){
            a=a*10+data[p]-0x30;
            p++;
        }
if(data[p]=='.'){
            p++;
while(data[p]<='9'&&data[p]>='0'){
                a=a*10+data[p]-0x30;
                c++;
                p++;
        }}
if(data[p]=='+'||data[p]=='-'){
if(data[p]=='+'){e=1;}
else {e=-1;}
            p=p+2;
            b=data[p]-0x30;
            p++;
while(data[p]<='9'&&data[p]>='0'){
                b=b*10+data[p]-0x30;
                p++;
            }

        }
break;
    }
    sum=a*f(e*b-c);
strcpy(token->name,"con");
    token->pos=pos_con;
    con[pos_con]=sum;
    pos_con++;
    token->next=(_token *)malloc(sizeof(_token));
    token=token->next;
    token->next=NULL;
printf("the num is %f\n",sum);
return p;
}

//对界符进行处理
//判断接下来的单词是否是界符
int IsDel(char check){
int i=0,ans=-1;
for(i;i<len_del;i++)
        {if(check==del[i]){
        ans=i;
break;
    }}
return ans;
}

int deal_Del(int p,char data[])
{
strcpy(token->name,"del");
    token->pos=IsDel(data[p]);
    token->next=(_token *)malloc(sizeof(_token));
    token=token->next;
    token->next=NULL;
printf("%c\n",data[p]);
    p++;
return p;
}